Network systems, such as transport management systems, provide support for logistical issues in managing the transportation of people, cargo, or the like. In some systems, a driver provides transportation services to a rider to a location selected by the rider. In typical systems, a rider requesting service is matched with one of a plurality of available drivers based at least in part on the pickup location, the destination location, the current location of the available driver, and a comparison of the requested pickup time at a pickup location and the estimated time of arrival of the driver at the pickup location. Typically, however, a rider is presumed to be at the pickup location when the request is made. Therefore, the rider's location and estimated time of arrival at the pickup location are not monitored after the rider makes the initial trip request, such that a driver could have to wait at the pickup location for several minutes if the rider is delayed. This may lead to inefficient allocation of resources, particularly in instances where there is high rider demand concentrated in a geographic region.